This document introduces the International System of Units (SI) used in chemistry. It defines the seven base SI units including meters, kilograms, kelvin, seconds, moles, and discusses common unit conversions like Celsius to kelvin, milligrams to grams, and grams to kilograms. It also explains the concept of density and how density determines whether an object will sink or float in a liquid.

1. Unit 1
SI UNITS

2. Units used in chemistry

3. SI units:
SI Base Units
Quantity SI base
unit
Symbol
Length meter m
Mass kilogram kg
Temperature kelvin K
Time second s
Amount of
substance
mole mol

4. Memorize:
1000 mg = 1 g
1000 g = 1 kg

5. Temperature conversions:
Celsius
Kelvin
100
divisions
100
divisions
100°C
Boiling point
of water
373.15 K
0°C
Freezing point
of water
273.15 K
Celsius + 273.15 = kelvin

6. Density

7. Density
0.53 g/cm3
10 g 10 g10 g 10 g
19 cm3
10 cm3 3.7 cm3
0.88 cm3
1.0 g/cm3
2.7 g/cm3 11.4 g/cm3

8. Sink or float?
It’s all about density. . .